This invention relates to tractors, such as compact farm and industrial tractors and large garden tractors, having a rear power take off shaft and carrying a rotary lawn mower and, more particularly, to a belt drive apparatus for driving the mower from the power take off shaft.
Conventionally, the direction of rotation of a power take off shaft on a farm tractor is clockwise as viewed from the rear and trailing powered farm implements, such as rotary tillers, are designed to be driven by a shaft turning in this direction. On the other hand, belly mounted rotary mowers, such as the three spindle rotary mower shown in the Marek et al. U.S. Pat. No. 3,283,486, are designed to be driven clockwise as viewed from the top to produce the conventional right side discharge. A standard mule drive, such as that shown with a front power take off in the Marek patent, will not produce the desired direction of rotation with a rear power take off. If the direction of rotation of the power take off shaft were reversed, as others have done, the tractor would no longer be suitable for use with other rear mounted implements which are dependent on the direction of rotation and designed in accordance with the convention of the art.
Various arrangements have been employed to achieve correct rotation of a right side discharge mower from a standard clockwise power take-off. One arrangement employs a right angle gear box, which is generally unsatisfactory because of the additional bulk, noise, and especially cost. Other arrangements employ mule belt drives with crisscrossed belts to reverse the drive which imposes severe twisting in the belt and, in some cases, causes the belt runs to rub together resulting in short belt life. On some drives, the belt may become so severely twisted that the belt comes off the pulleys. In other belt drives, the back of the belt is bent over a pulley which further reduces belt life.